The specificity of age-related oxidative damage to proteomes is largely unknown. Our long-term goal is to develop new proteomic strategies capable of identifying proteins susceptible to such damage. In this exploratory R21 application, our short-term goal is to use the concept of subcellular proteomes, carbonyl immuno-capture, and ICAT technology to identify (and discover) age-related carbonyl-associated proteins in muscle mitochondria. We will use the Fisher 344 rat as an animal model. We will compare the proteomes of two muscles whose functions decline differently with aging, the soleus and semimembranosus. While the soleus is significantly dependent on mitochondria for ATP production, the semimembranosus relies on glycolysis as a source of ATP. As a result, it is hypothesized that different ROS production patterns will cause different protein oxidative damage in these two muscles. Two studies are proposed: (1) direct comparison of carbonyl-associated proteins in the two muscle types at 6 and 28 months of age; (2) a longitudinal study with muscle sampling from the same animal at three different ages. Sample limitations in the second study will be addressed by using FT-ICR-MS and CE-LIF. [unreadable] [unreadable]